Of the 5 million Americans with failing hearts, about half of them will die within five years of getting diagnosed. Given the odds, it seems that people with heart failure should start thinking about how they want to die.

But doctors don't routinely talk to those patients about end-of-life planning.

When researchers asked 50 doctors and 45 nurse practitioners and physician assistants how often they discuss preparing for death with their heart failure patients.

A third of the providers said they lacked confidence in talking about end-of-life care. Only 12 percent said they have routine yearly discussions about the end of life.

"The common reasons are that they're uncomfortable, they may not have enough time, or they sense that the patient or the family is not ready to have those discussions," says Dr. Shannon Dunlay, a cardiologist at the Mayo Clinic in Rochester, Minn., who led the study.

The findings were presented Wednesday at the Quality of Care and Outcomes Research conference in Baltimore. The abstract was peer-reviewed, but the results have not yet been published

The doctors and nurses were from three Mayo clinics and practices affiliated with the Mayo Clinic Health System, which is known for being ahead of the game in basing medical care on current best practices.

"When we asked providers if they were asking those questions, most of them said they do when the situation declines or when they're discussing a new intervention," says Dunlay.

But it's hard to predict when a patient might decline.

"There are people I think are going to do well, and then they don't," says Dr. Larry Allen, a cardiologist at the University of Colorado Anschutz Medical Center in Denver, who researches end-of-life expectations and care. "On the flip side, there are people with lots of risk factors. If I tell them they might not do well, and then they do, it can create unnecessary anxiety and diminish trust."

End-of-life conversations are a routine part of Allen's job. They involve asking tough questions like: Would you want a feeding tube or CPR? If you can't breathe, would you want a tube placed down your throat to help you breathe? Are you trying to live as long as possible, or is your goal to maximize your quality of life? Do you want to die in your sleep?

Allen says that often patients with a mechanical heart pump or an implanted defibrillator, which delivers electric shocks to a languishing heart, might not have decided at what point they want the device turned off.

"When people are dying of progressive heart failure ... dying of an arrhythmia may not necessarily be a bad thing at that point," Allen, who was not involved in the study, told Shots. "When people are potentially dying, you don't want to be giving them electric shocks on top of that."

One of the top reasons doctors cited for their reluctance in asking those questions was destroying a patient's sense of hope in surviving.

"But actually," Dunlay says, "patients who talk about those things tend to feel better about their condition."

One solution, Allen suggests, could be to encourage healthcare providers to have those conversations annually with patients, no matter what condition the patient is in at the moment. That's particularly important because a patient's attitude toward handling death can change over time, and because heart failure patients tend to overestimate how long they'll live.

Dunlay agrees, saying it's better to do so on a regular basis rather than putting it off until it's too late.

Providers aren't being taught how to broach tough subjects, Dunlay adds, but most of the survey participants were interested in further training.